/Engine/Source/Runtime/RHI/Public/RHIContext.h
void RHIDrawIndexedIndirect ( [FRHIBuffer](API\Runtime\RHI\FRHIBuffer) * IndexBufferRHI, [FRHIBuffer](API\Runtime\RHI\FRHIBuffer) * ArgumentsBufferRHI, int32 DrawArgumentsIndex, uint32 NumInstances )